Sorted By Test Name - Mayo Medical Laboratories

ALP
8340
sodium excretion should exceed 200 mEq to document adequate sodium repletion. See Renin-Aldosterone
Studies in Special Instructions. Note: Advice on stimulation or suppression tests is available from Mayo
Clinic's Division of Endocrinology and may be obtained by calling Mayo Medical Laboratories.
Reference Values:
0-30 days: 0.7-11.0 mcg/24 hours*
1-11 months: 0.7-22.0 mcg/24 hours*
> or =1 year: 2.0-20.0 mcg/24 hours
*Loeuille GA, Racadot A, Vasseur P, Vandewalle B: Blood and urinary aldosterone levels in normal
neonates, infants and children. Pediatrie 1981;36:335-344
Clinical References: 1. Young WF Jr: Primary aldosteronism: A common and curable form of
hypertension. Cardiol Rev 1999;7:207-214 2. Young WF Jr: Pheochromocytoma and primary
aldosteronism: diagnostic approaches. Endocrinol Metab Clin North Am 1997;26:801-827
Alkaline Phosphatase, Serum
Clinical Information: Alkaline phosphatase (ALP) is present in a number of tissues including liver,
bone, intestine, and placenta. Serum ALP is of interest in the diagnosis of 2 main groups of conditionshepatobiliary
disease and bone disease associated with increased osteoblastic activity. A rise in ALP
activity occurs with all forms of cholestasis, particularly with obstructive jaundice. The response of the
liver to any form of biliary tree obstruction is to synthesize more ALP. The main site of new enzyme
synthesis is the hepatocytes adjacent to the biliary canaliculi. ALP also is elevated in disorders of the
skeletal system that involve osteoblast hyperactivity and bone remodeling, such as Paget's disease, rickets
and osteomalacia, fractures, and malignant tumors. Moderate elevation of ALP may be seen in other
disorders such as Hodgkin's disease, congestive heart failure, ulcerative colitis, regional enteritis, and
intra-abdominal bacterial infections.
Useful For: Diagnosis and treatment of liver, bone, intestinal, and parathyroid diseases.
Interpretation: The elevation in ALP tends to be more marked (more than 3 fold) in extrahepatic
biliary obstruction (e.g., by stone or by cancer of the head of the pancreas) than in intrahepatic
obstruction, and is greater the more complete the obstruction. Serum enzyme activities may reach 10-12
times the upper limit of normal, returning to normal on surgical removal of the obstruction. The ALP
response to cholestatic liver disease is similar to the response of gamma-glutamyltransferase (GGT), but
more blunted. If both GGT and ALP are elevated, a liver source of the ALP is likely. Among bone
diseases, the highest level of ALP activity is encountered in Paget's disease as a result of the action of the
osteoblastic cells as they try to rebuild bone that is being resorbed by the uncontrolled activity of
osteoclasts. Values from 10-25 times the upper limit of the reference interval is not unusual. Only
moderate rises are observed in osteomalacia, while levels are generally normal in osteoporosis. In rickets,
levels 2-4 times normal may be observed. Primary and secondary hyperparathyroidism are associated with
slight to moderate elevations of ALP, the existence and degree of elevation reflects the presence and
extent of skeletal involvement. Very high enzyme levels are present in patients with osteogenic bone
cancer. A considerable rise in ALP is seen in children following accelerated bone growth. In addition, an
increase of 2-3 times normal may be observed in women in the third trimester of pregnancy, although the
interval is very wide and levels may not exceed the upper limit of the reference interval in some cases.
The additional enzyme is of placental origin.
Reference Values:
Males
4 years: 149-369 U/L
5 years: 179-416 U/L
6 years: 179-417 U/L
7 years: 172-405 U/L
8 years: 169-401 U/L
9 years: 175-411 U/L
10 years: 191-435 U/L
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